Ask Dr. Math

High School Archive

Browse High School Physics/Chemistry

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Gravity and Acceleration [06/24/2002]

How fast do you have to travel to experience a force of 1 G?

Half-Life [06/24/2001]

What is a half-life?

Harmonic Mean [12/15/1996]

What is the harmonic mean and how do you use it?

Heat Supplied and Heat Loss of a Furnace [05/17/2000]

Heat is supplied by a furnace at a constant rate, but is lost at a rate determined by the difference between its temperature and the temperature of its surroundings...

The Heaviside Step Function [09/03/2003]

How can I construct a term that is zero when the input is below some limit, but nonzero above it?

Heisenberg Uncertainty Principle [01/01/2002]

When you look at the Heisenberg Uncertainty Principle, Plank's Constant becomes zero. Is Plank's Constant wrong, or the Uncertainty Principle?

How Fast Does the Man Fall? [5/22/1996]

If a 180 lb. man drops 1150 feet from a building, how many km per hour will he be going when he hits the ground?

How High Did My Rocket Go? [05/28/1999]

We were 15 feet away from a rocket at launch and measured an angle of 89 degrees on the first launch and 67 degrees on the second. Can you tell me how high it went?

How High? How Fast? [07/17/2002]

If you throw a ball straight up at 100 mph, how high would it go? And how fast would it be moving when it came back down?

How Long is the Stone in the Air? [8/5/1996]

A stone is thrown from the ground and returns to the ground... what is the total time of flight?

How Long Until the Bomb Hits the Ground? [8/25/1996]

A bomber flying at 32,000 feet over level terrain drops a 500-pound bomb...

How Many Dimensions Are There? [03/29/2001]

How do we know how many dimensions there are? What is the significance of drawing 4D hypercubes? If I were in a 2D world, how would I be able to represent 3D objects?

How Much is a Mole? [11/17/2000]

How many grams are in a mole?

If the Earth Stopped Rotating... [05/11/2000]

If the Earth were to stop rotating, would objects weigh less or would they weigh more?

Imaginary Numbers [02/28/1999]

What jobs and professions use imaginary numbers?

Index of Refraction [10/10/2001]

How deep is the water in the pool?

Integration and the Concept of Work [3/19/1996]

If asked to find the work done by a varying force F(x) = 4x^3 from -4 to +4, using integration the work done equals 0. How can it be physically that no work is done when applying this force over a distance of 8 units?

Interpolation Polynomials and Linear Regression [10/09/1998]

I need to find the polynomial of a temperature curve using some data I have gathered.

Interpretation of the Derivative [2/2/1996]

Derivatives incorporate a temporal component with a spatial component...

Is an Electron a Particle or a Wave? [12/02/1999]

Can you explain to me whether the electron is a particle or a wave? Electrons diffract like a wave, but also have a mass like a particle. How does this work?

Is There Any Difference between Reaction Force and Normal Force? [01/26/2008]

Do reaction force and normal force mean the same kind of force? Must the normal force always be perpendicular to the surface acted upon? What about reaction force? If a force of, say, 10 N acts on a surface at a 45 degree angle, what are the degrees of normal force and reaction force? Should the normal force always be 90 degrees, regardless of the angle of the original force?

Jerk - Derivative of Acceleration [03/16/2001]

I need a mathematical term that begins with the letter J, its definition, and a high-school-level explanation of the term.

Kinematics - Finding Rocket Height and Speed [10/15/2001]

During a test a rocket is traveling upward at 75m/s, and when it is 40 m from the ground its engine fails. What is the maximum height reached by the rocket, and what is its speed just before it hits the ground?

Lever Word Problem [01/14/2003]

If a person has a 3-foot wrecking bar and places a fulcrum 3 inches from one end, how much can he lift if he applies a force of 50 pounds to the long end?

Lifting an Object of Changing Mass [7/28/1996]

Suppose you grab the end of a chain that weights 3 lb/ft and lift it straight up off the floor at a constant speed of 2 ft/s: determine the force as a function of height; how much work do you do in lifting the top of the chain 4 feet?

Light and the Theory of Relativity [10/15/1997]

Based on the theory of general relativity, where the faster something goes, the slower time goes, how come light can go anywhere?

Magnitudes of Vectors Don't Add Up [11/14/2010]

A student does not understand the magnitude that results from adding two vectors. With worked examples both abstract and concrete, Doctor Ian clears up the confusion before evoking the triangle inequality on the face of an analog clock.

Mass and Weight [08/16/1997]

Why are mass and weight both measured with the same unit? If weight is different on the moon and mass is not, what is the difference?

Mass Gain in Relativity [06/06/1999]

At what speeds would an object experience a 400% gain in mass according to the theory of relativity?

Massless Cable [05/06/2003]

Why is are cables considered to be massless in a system?

Mass versus Weight [09/09/99]

Do mass and weight refer to the same thing on earth? Is mass equal to weight?

Mass vs. Weight [05/27/1999]

If you calibrated a scale to read pounds (mass) on earth and took it to the moon, how would you calculate mass and weight on the moon?

Math and Makeup [01/05/2002]

My teacher told us that everything relates to math. I was wondering how makeup relates to math.

Math and Music: Harmonic Series [01/09/1998]

Could you supply me with information on how math relates to music?

The Math Behind Music: Pitches, Scales, Geometry [12/03/1997]

Connections between music, physics, and math.

Mathematics of Projectile Motion [7/7/1996]

A stone is thrown to hit a bird at the top of a pole. At the instant the stone is thrown, the bird flies away in a horizontal straight line... find the horizontal component of the velocity of the stone.

Math-science Materials on Flight [6/16/1996]

We are looking for math-science materials on flight for grades 7-9, for beginning to very advanced students.

Maximizing Horizontal Distance [04/10/1998]

Using algebra, prove that an object needs to be thrown at 45 degrees to travel the greatest possible horizontal distance.

Meaning of Derivative [10/12/1996]

What's a plain English meaning of the derivative?

Measurements on a Logarithmic Scale [11/21/1998]

What kinds of measurements are done on a logarithmic scale? What physical properties make a logarithmic scale more appropriate?

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